Guar gum gives me the same problem as xanathan gum. Avocado??! That's interesting. Not sure how I'd get round the colour issue (can't quite see it working with raspberries!) but maybe a nut-flavoured one - eg toasted hazelnut??My mind immediately goes to Guar gum. I've never really had to cook for dietary consideration.
OH! Or avocado! It sounds weird, but it's pretty neutral in ice cream.